“The great and still ongoing declines in fertility that are sweeping through the Muslim world most assuredly qualify as a “revolution” – a quiet revolution, to be sure – but a revolution in which hundreds of millions of adults are already participating: and one which stands to transform the future,” writes demographer Nicholas Eberstadt in the June 2012 issue of Policy Review, the journal of Stanford University’s Hoover Institution. 
Eberstadt and co-author Apoorva Shah conclude, “The remarkable fertility declines [sic] now unfolding throughout the Muslim world is one of the most important demographic developments in our era. Yet it has been ‘hiding in plain sight’ – that is to say, it has somehow gone unrecognized and overlooked by all but a handful of observers, even by specialists in the realm of population
studies. Needless to say, such an oversight is more than passing strange, and we do not propose to account for it here.”
As Eberstadt and Shah indicate, the evidence has been in the public domain for years, and well known to demographers. “In most of the Islamic world it’s amazing, the decline in fertility that has happened,” Hania Zlotnik, head of the United Nations’ population research branch, told the New York Times in 2009.  As early as 2008, a study by the Institute for Applied Systems Analysis concluded, “A first analysis of the Iran 2006 census results shows a sensationally low fertility level of 1.9 for the whole country and only 1.5 for the Tehran area (which has about 8 million people) … A decline in the TFR [total fertility rate] of more than 5.0 in roughly two decades is a world record in fertility decline.”
Nonetheless, as Eberstadt muses, none but a handful of observers in the world of public policy world took notice. As one among this handful – Eberstadt and Shah kindly cite my 2011 book How Civilizations Die (and Why Islam is Dying, Too) – I also find it “passing strange” that the fastest demographic decline in recorded history has evoked so little interest. Perhaps the explanation is that the facts, however startling, do not suit the political narratives either of the mainstream left or right.
Demographic decline belies the liberal belief, encapsulated in President Barack Obama’s June 4, 2009 Cairo speech, that a modernizing Muslim world can become a friendly partner of the United States. At the same time, the demographics make short work of the so-called realist argument that America can promote stability in regions with Muslim majorities by backing pro-Western autocracies.
But they also undermine the mainstream conservative view that nation-building, regime change, or support for pro-democracy movements can redeem Muslim countries. The Muslim demographic spiral bespeaks, rather, a dismal future of chaotic and disruptive decline in many of the most important Muslim countries, including adversaries like Iran as well as such putative allies as Turkey.
None of the well-defined currents in the American foreign policy debate, in short, is inclined to consider an uncertain future in which American ministrations must fail, because the societies in question are failing. The implications are unpleasant to consider, so the foreign policy establishment of both parties prefers not to consider them at all. In fact, it would be unsettling if Americans were to conclude too glibly that many Muslim-majority countries have little to expect apart from decline and deterioration. Nonetheless the evidence points to this conclusion.
The Muslim world’s affliction is spiritual rather than material, as Prof Eberstadt argues eloquently, if indirectly. None of the usual quantitative predictors of population growth appear to explain the fact that Muslim countries show the fastest population decline of any segment of the world’s population. Statistically, he shows, it is the fact of being Muslim as suchthat has the most significance of all the variables that might explain population decline! That is a startling assertion, even if it is embedded in what at first glance seems a dry statistical exposition. Eberstadt and Shah comment:
People in the Ummah can be expected, today, to have fewer children than people in non-Muslim societies. Why should this be so? “Developmentalist” theories, with their emphasis on the primacy of material and structural transformations, cannot offer much insight into this mystery … “Developmentalist” perspectives cannot explain the great changes underway in many of these countries and territories – in fact, various metrics of socioeconomic modernization serve as much poorer predictors of fertility change for Muslim-majority populations than for non-Muslim populations.
Not to put too fine a point on it: Proponents of “developmentalism” are confronted by the awkward fact that fertility decline over the past generation has been more rapid in the Arab states than virtually anywhere else on earth – while well-informed observers lament the exceptionally poor development record of the Arab countries over that very period. Put another way: Materialist theories would appear to come up short when pressed to account for the dimensions of fertility change registered in large parts of the Ummah over the past generation. An approach that focuses on parental attitudes and desires, their role in affecting behavior that results in achieved family size, and the manner in which attitudes about desired family size can change with or without marked socioeconomic change may prove more fruitful here.
While pointing out the inadequacy of “materialist” explanations of Muslim demographic decline, Eberstadt and Shah do not go so far as to offer a spiritual explanation (although they generously to “salute” my “wide-ranging and provocative exposition” in How Civilizations Die).
In my book, I contend that faith and fertility are inseparable, because a nation that has faith in its future will bring new generations into the world, while a nation that has lost faith in itself will not trouble to do so. The faith of Christians and Jews can thrive in modernity – witness America and Israel, by many gauges the most modern among industrial nations as well as the most religious and most fertile. But modernity and Islam appear incompatible. As soon as Muslims (and especially Muslim women) become literate, fertility drops below replacement, as in Iran, Turkey, Algeria and Tunisia.
As noted, Eberstadt and Shah demonstrate that none of the usual predictors of population growth rates (gross domestic product per capita, literacy, and so forth) explain the much lower fertility of Muslim (and especially Arab Muslim countries) within the universe of developing countries. The best explanation is the bare fact of having a Muslim majority. As I observe in my book, though, among the universe of Muslim countries itself, though, the literacy rate is a very strong predictor of relative fertility and population growth.
30 Muslim-majority countries, literacy vs population growth
Source: United Nations, author’s calculations
This analysis is consistent with Eberstadt and Shah’s implicit argument that spiritual rather than material circumstances explain the Muslim fertility decline. Education in this case is a proxy for the transition of Muslims, and especially Muslim women, out of traditional society into a modernity that does not host Muslim mores. Where data is available within individual Muslim countries, I reported in my book, demographers have found a close relationship between fertility and education by cohort of population. Exemplary in this regard is the IIASA’s 2008 paper “Education and the World’s Most Rapid Fertility Decline in Iran,” by a team of demographers headed by Wolfgang Lutz. 
Sketching the potential consequences of the demographic revolution for the Ummah, Eberstadt and Shah call attention to the economic consequences of rapid aging in poor countries, a problem I characterized as a “train wreck.” They warn of the impact of rapid population aging on relatively low income levels”:
The lower a country or territory’s fertility, the more powerful the demographic pressure for population aging over the subsequent generation. With extremely rapid fertility decline – and the descent into sub-replacement fertility – a number of Muslim-majority populations are already set on course for very rapid population aging. Over a dozen Muslim-majority populations, under current US Census Bureau projections, would have higher fractions of their national populations over the age of 65 by 2040 than the US. today. Today these same places enjoy only a fraction of US per capita income levels … How these societies will meet the needs of their graying populations on relatively low income levels may prove to be one of the more surprising and unanticipated challenges of the fertility revolution now underway in the Ummah.
Eberstadt and Shah have put their finger on the crucial issue, one which Western strategists dare not ignore. Iran is keenly aware of its demographic decline – its leaders and elite have wrung their hands about the problem in public for years. The imminent decline and prospective collapse of Iranian society under the crushing burden of a fast-aging population constitutes a strong motive for Iran to assert itself today, while it still can. Iran knows that it must break out, or break down. It does not seek stability and preservation of its existing power, as President Obama has stated on a number of occasions, for Iran’s leaders know that stability means a catastrophic and terminal decline. It has nothing to lose and everything to gain by taking strategic risks, for example, nuclear weapons development.
For this among other reasons, Eberstadt’s and Shah’s new paper is a timely and important contribution to a strategic debate of existential importance to the West.